Coordination, communication, and common knowledge; A retrospective on the electronic-mail game

Common knowledge plays an important role in coordination problems and coordination problems are central to many areas of economic policy. In this paper, I review some common-knowledge puzzles culminating in the electronic-mail game. These puzzles may seem distant from practical concerns. However, I then argue why insights derived from this literature are useful in interpreting empirical evidence of how people coordinate under uncertainty and in understanding the role of communication in coordinating behaviour.